Although distressing to many parents, infants and toddlers sucking their thumb is a common if not universal habit. Most children phase out of it by around age 4, usually with no ill effects. But thumb-sucking continuing into late childhood could prove problematic for a child’s bite.

Thumb sucking is related to how young children swallow. All babies are born with what is called an infantile swallowing pattern, in which they thrust their tongues forward while swallowing to ensure their lips seal around a breast or bottle nipple when they nurse. Thumb-sucking mimics this action, which most experts believe serves as a source of comfort when they’re not nursing.

Around 3 or 4, their swallowing transitions to a permanent adult swallowing pattern: the tip of the tongue now positions itself against the back of the top front teeth (you can notice it yourself when you swallow). This is also when thumb sucking normally fades.

If a child, however, has problems transitioning to an adult pattern, they may continue to thrust their tongue forward and/or prolong their thumb-sucking habit. Either can put undue pressure on the front teeth causing them to move and develop too far forward. This can create what’s known as an open bite: a slight gap still remains between the upper and lower teeth when the jaws are shut rather than the normal overlapping of the upper teeth over the lower.

While we can orthodontically treat an open bite, we can minimize the extent of any treatments if we detect the problem early and intervene with therapies to correct an abnormal swallowing pattern or prolonged thumb sucking. For the former we can assist a child in performing certain exercises that help retrain oral and facial muscles to encourage a proper swallowing pattern. This may also help diminish thumb sucking, but we may in addition need to use positive reinforcement techniques to further discourage the habit.

To stay ahead of possible problems with thumb sucking or the swallowing pattern you should begin regularly taking them to the dentist around their first birthday. It’s also a good idea to have an orthodontic evaluation around age 6 for any emerging bite problems. Taking these positive steps could help you avoid undue concern over this common habit.